Decidim up to 0.30.8/0.31.4/0.32.0.rc1 Identity-Document Verification Admin UI verification_attachment blobs improper authorization

Summaryinfo

A vulnerability was found in Decidim up to 0.30.8/0.31.4/0.32.0.rc1. It has been declared as problematic. This affects an unknown function of the file verification_attachment blobs of the component Identity-Document Verification Admin UI. Executing a manipulation can lead to improper authorization. This vulnerability is tracked as CVE-2026-45378. The attack can be launched remotely. No exploit exists.

Detailsinfo

A vulnerability classified as problematic was found in Decidim up to 0.30.8/0.31.4/0.32.0.rc1. This vulnerability affects some unknown processing of the file verification_attachment blobs of the component Identity-Document Verification Admin UI. The manipulation with an unknown input leads to a improper authorization vulnerability. The CWE definition for the vulnerability is CWE-285. The product does not perform or incorrectly performs an authorization check when an actor attempts to access a resource or perform an action. As an impact it is known to affect confidentiality. CVE summarizes:

Decidim is a participatory democracy framework. Prior to 0.30.9, from 0.31.0 before 0.31.5, and in 0.32.0.rc1 before 0.32.0.rc2, the identity-document verification admin UI embeds verification_attachment blobs through reusable signed Active Storage disk URLs, allowing anyone who obtains a URL to download the scanned document without an authenticated Decidim session until the signature expires. Verification-document images are rendered with variant_url(...), which produces signed /rails/active_storage/disk/... links instead of routing the file through an authorization-checking controller. Because Decidim configures Active Storage service URLs to remain valid for seven days, the URL itself becomes the credential for that period. The affected files are verification_attachment blobs on Decidim::Authorization, and the admin review pages embed those signed URLs directly into the HTML for pending and confirmation views. This issue is fixed in versions 0.30.9, 0.31.5, and 0.32.0.rc2.

The advisory is shared for download at github.com. This vulnerability was named CVE-2026-45378 since 05/12/2026. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. There are known technical details, but no exploit is available. The MITRE ATT&CK project declares the attack technique as T1548.002.

Upgrading to version 0.30.9, 0.31.5 or 0.32.0.rc2 eliminates this vulnerability.

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Productinfo

Name

• Decidim

Version

• 0.30.0
• 0.30.1
• 0.30.2
• 0.30.3
• 0.30.4
• 0.30.5
• 0.30.6
• 0.30.7
• 0.30.8
• 0.31.0
• 0.31.1
• 0.31.2
• 0.31.3
• 0.31.4
• 0.32.0.rc1

Website

• Product: https://github.com/decidim/decidim/

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